#include"cmath"
#include <iostream>
using namespace std;
int main()
{
	int i=1,n=0;
	typedef bool flag ;
	flag f=1;
	cout<<"Please enter a number:";cin>>n;
	for(i=2;i<=sqrt(n);i++)
		if(float(n)/i==(n/i)) {f=0;break;}
	(f)?cout<<"It is":cout<<"it isn't";
	return 0;
}
